I'm about to fabricate my engine cradle and had plannned to utilise my engine as a stressed chassis member.

I've just noticed that with a little work, my old rubber based X-Flow mounts would also do a very tidy (and lighter) job of it.

Thing is... do I want any play (albeit minimal) in the engine movement? Does anyone foresee any problems?

Ive mounted my R1 rigidly in the chassis, only keeping the small rubber inserts inside the mount on top of the gearbox. My previous blade engine was partially mounted on poly bushes and that was Ok too, you don't want too much movement though because it might start upsetting the gear linkage etc.

BTW, don't the Xflow mounts sit low in the chassis either side of the engine? If so I can't envisage how these could be effectively modified to support a bike engine?

I would have made 2 'half cradles' at either side of the engine to attach to the X-Flow mounts.

As most of the engine mounts you need to pick up on are at the top of the engine, Im not convinced that would work very well, or be any lighter but might be wrong.

Have a look at the way Westfield do theirs, basically a big X brace picking up on the engine and gearbox mounts which also has the advantage of bracing the chassis itself as well.

You can kind-of see it in this pic, Im sure there are better ones around though

Cheers Chris. That looks quite neat.